The invention concerns an acceleration-compensated pressure transducer.
For measuring dynamic pressure phenomena in gaseous or liquid media, especially in engines and turbo systems, there is a need for pressure transducers that can be mounted directly in the vibrating housing walls of such machines without the acceleration forces of these interfering with the pressure signal being measured. Usually piezoelectric pressure transducers are used for such measurements, especially where highly dynamic processes or measurements in temperature ranges above 200.degree. C. are involved.
In some applications, it is enough to fit the pressure transducers into the vibrating machine walls by elastically supported adapters. In higher temperature ranges, this is not generally possible. Thus, for years, piezoelectric acceleration elements have been integrated in the pressure transducers to detect the acceleration forces separately. This entails much technical outlay, because an additional piezo-element, mostly in the form of one or more crystal plates, has to be fitted counterconnected to the pressure signal crystal array. This reduces the useful pressure signal by at least 1/3 of the maximum value. This is a further great disadvantage because in many cases amplitudes of a few millibars must be measured. Moreover, it has been shown that the acceleration compensation obtainable by the familiar countermeasures may be influenced very considerably by socket or metal cable connections, i.e. if additional masses are connected to the pressure transducer housing.
It is the purpose of the invention to simplify technically pressure transducers of the known kind and exclude the influences of the various connection methods. This is achieved by dividing the pressure transducer into a measuring inner part and a housing-like outer part and joining the two together only at the diaphragm flange part, a freely vibrating measuring system is obtained, which regardless of its housing measures, vibrates and compensates accelerations and vibrations.